The present disclosure relates to a development device configured to supply a developer to an image carrier and to an image forming apparatus including the same.
An electrophotographic image forming apparatus is configured to form an image through processes of forming an electrostatic latent image by irradiating a beam formed on the basis of image information to a circumferential surface of an image carrier (a photosensitive drum), of transferring a toner image formed by supplying a toner (a developer) to the electrostatic latent image from a development device on a sheet, and of carrying out a fixing process.
In recent years, with advances of color printing and high-speed processing, a configuration of the image forming apparatus is becoming sophisticated and rotational speed of a toner agitation member in the development device is being increased. According to this, a pressure within the development device becomes positive, i.e., higher than an atmospheric pressure. Due to that, the toner floats from an inside of the development device, is discharged out of an opening facing to the photosensitive drum, and contaminates an inside of an apparatus main body of the image forming apparatus. It has also become difficult to supply a required toner to the electrostatic latent image on the photosensitive drum.
In particular, in the development device, there is a case where the scattered toner accumulates around a blade regulating an amount of the developer to be carried on a developer carrier. If the accumulated toner coagulates and adheres on a developing roller, a fall of toner occurs, thereby causing an image defect.
In order to solve such a problem, there is a development device in which an elliptic roller is disposed in a concave part formed on a wall provided between an area where a developing roller faces to a photosensitive drum and an ear-breaking blade and in which a film member is attached so as to cover the concave portion by fixing an upper end part thereof and leaving a lower end part as a free end. In the development device, by rotating the elliptic roller, a convex part of the elliptic roller pushes up the film member to largely move the free end side of the film member. According to this, the toner is prevented from accumulating on the film member.
There is also a development device including a toner receiving member, a sheet member and a vibration motor. The toner receiving member has a wall part provided between an area where a developing roller faces to a photosensitive drum and an ear-breaking blade and is disposed in a substantially whole longitudinal area of the wall part to receive the toner falling from the developing toner. The sheet member is pasted on a surface of the toner receiving member. The vibration motor has an exciting weight attached to an output shaft in order to vibrate the toner receiving member. This development device prevents the toner from accumulating on the film member by rotationally driving the vibration motor to vibrate the toner receiving member.
However, in the former development device mentioned above, although the largely movable free end side prevents the toner from accumulating on the film member, there is a possibility that the barely movable fixed end side cannot sufficiently prevent the toner from accumulating on the film member.
Regarding this point, in the latter development device mentioned above, because the toner receiving member on which the film member is pasted vibrates by the drive of the vibration motor, the toner is prevented from accumulating on the film member. However, the latter development device mentioned above needs to be provided with a mechanism that permits fine movements of the vibration motor, wiring and the toner receiving member, and others within the development device. In the latter development device mentioned above, because the film member needs to be pasted on the toner receiving member, there are problems that it is inevitable to enlarge and complicate the development device and to increase costs and an assembly time.